Efflorescence

Noun

(construction) An encrustation of soluble salts, commonly white, deposited on the surface of stone, brick, plaster, or mortar; usually caused by free alkalies leached from mortar or adjacent concrete as moisture moves through it.

(pathology) A redness, rash, or eruption on the skin.

(botany) The production of flowers.

(metaphorical) Rapid flowering of a culture or civilisation etc.

(chemistry) The formation of a powdery surface on crystals, as a hydrate is converted to anhydrous form by losing loosely bound water of crystallization to the atmosphere.

(geology) An encrustation of soluble salts, deposited on rock or soil by evaporation; often found in arid or geothermal environments.